Photographic products, compositions and processes employing azo dye developers



3,l3,ll89 Patented May 11, 1965 3,183,089 PHOTOGRAPHIC PRODUCTS,COMPOSITIONS 'AND PROCESSES EMPLOYING AZO DYE DEVELOPERS Myron S. Simon,Newton Center, Mass., assignor to Polaroid Corporation, Cambridge,Mass., a corporation of Delaware No Drawing. Filed May 21, 1962, Ser.No. 196,523

39 Claims. (Cl. 9629) This invention relates to photography and moreparticularly to products, compositions and processes for the developmentof photosensitive silver halide elements.

It is one object of the present invention to provide novel processes andcompositions for the development of silver halide emulsions, in whichnovel colored silver halide developing agents are used.

Another object is to provide novel processes and compositions for thedevelopment of silver halide emulsions, in which the novel silverhalide-developing agent is capable of developing an exposed silverhalide emulsion and imparting a reversed or positive colored image ofthe developed image to a superposed image-receiving material.

Further objects are to provide said novel silver halide developingagents, and novel products, processes and compositions suitable for usein preparing monochromatic and multichromatic' photographic images bythe employment of said novel silver halide developing agents.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention acordingly comprises the processes involving theseveral-steps and the relation and order of one or more of such stepswith respect to each of the others, and the products and compositionspossessing the features, properties and the relation of elements whichare exemplified in the following detailed disclosure, and the scope ofthe application of which will be indicated in the claims.

The objects of this invention may be accomplished by the use of certainnovel dyes which have the ability to develop an exposed silver halideemulsion; thus these dyes may be referred to as dye developers. Thesenovel dyes or dye developers will be further described hereinafter. r

'The dye developers and the photographic processes and compositionsdisclosed herein are particularly useful in the treatment of ah exposedsilver halide emulsion, whereby a positive dye image may be imparted toanother element, herein referred to as an image-carrying orimagereceiving element. '1

US. Patent No. 2,983,606, issued May 9, 1961, to Howard G. Rogers,discloses diffusion transfer processes wherein a photographic negativematerial, such as a photographic element comprising an exposed silverhalide emulsiomis developed in the presence of a dye developer to impartto an image-receiving layer a reversed or positure or other-conditions.

tive dye image of the developed image by permeating into sensitiveelementcontains a layer of dye developer, and

the liquid processing composition is applied to the photosensitiveelement in a uniform layer as the photosensitive element is brought intosuperposed position with an imagereceiving element. The liquidprocessing composition permeates the emulsion to provide a solution ofdye developer substantially uniformly distributed therein. As theexposed silver halide emulsion is developed, the oxidation product ofthe dye developer is immobilized or precipitated in situ with thedeveloped silver, thereby providing an imagewise distribution ofunoxidized dye developer dissolved in the liquid processing composition.This immobilization is apparently due, at least in part, to a change inthe solubility characteristics of the dye developer upon oxidation, andespecially as regards its solubility in alkaline solutions. It may alsobe due, in part, to a tanning effect on the emulsion by the oxidizeddeveloping agent. At least part of this imagewise distribution ofunoxidized dye developer is transferred, by imbibition, to a superposedimage-receiving layer. The image-receiving layer receives a depthwisediffusion, from the emulsion, of unoxidized dye developer, withoutappreciably disturbing the imagewise distribution thereof, to provide areversed or positive, colored image of the developed or negative image.The image-receiving element may contain agents adapted to mordant orotherwise fix the diffused, unoxidized dye developer. Imbibition periodsof approximately one minute have been found to give good results, butthis contact period may be adjusted where necessary to compensate forvariations in tempera The desired positive image is revealed byseparating the image-receiving layer from the silver halide emulsionat-the end of the imbibition period.

The dye developer of this invention may be utilized in thephotosensitive element, for example in, on or behind the silver halideemulsion, or they may be utilized in the image receiving element or inthe liquid processing composition. In a preferred embodiment, a coatingor layer of the dye developer is placed behind the silver halideemulsion, i.e., on the side of the emulsion adapted to be located mostdistant from the photographed subject when the emulsion is exposed andpreferably also adapted to be most distant from the image-receivinglayer when in superposed relationship therewith. Placing the dyedeveloper behind the emulsion layer, as in the preferred embodiment, hasthe advantage of providing increased contrast in the positive image, andalso minimizes any light-filtering action by the colored dye developer.In this preferred embodiment, the layer of dye developer may be appliedby using a coating solution containing, e.'g., about 0.5 to 8%, byweight, of the dye developer. Similar concentrations may be used if thedye developer is utilized as a component of the liquid processingcomposition. In an especially useful mode of disposing the dyedevelopers in the photo-sensitive elements, the dye developer isdissolved in a water-immiscible solvent and then dispersed in a gelatincoating solution.

The liquid processing composition which is used in the processes hereindisclosed comprises at least an aqueous solution of an alkalinecompound, for example, diethylamine, sodium hydroxide or sodiumcarbonate, and may contain the dye developer. 'In some instances, it maycontain an additional silver halide developing agent. If the liquidprocessing composition is to be applied to the emulsion by being spreadthereon, preferably in a relatively thin, uniform layer, it may alsoinclude a viscosityincreasing compound constituting film-formingmaterial of the type which, when spread over a water-absorbent base,will form a relatively firm and relatively stable film. A preferredfilm-forming material is a high molecular weight polymer such as apolymeric, water-soluble ether inert to an alkali solution, as, forexample, a hydroxyethyl cellulose or sodium carboxymethyl cellulose.Other film-forming materials or thickening agents whose ability whereinY is a para-dihydroxyphenyl or an ortho-dihydroxyphenyl group which alsomay be nuclear substituted 1 by alkyl or halogen groups; Ar is adivalent aryl nucleus, such as a benzene or naphthalene nucleus,directly attached to the phenyl ring of Y; each Z is an alkyl group,preferably a lower alkyl group such as methyl or ethyl, an alkoxy group,preferably a lower alkoxy group such as methoxy, or a halogen, such aschlorine; n is O, 1 or 2; m is 1 or 2; said aryl nucleus Ar beingdirectly attached to the phenyl ring of Y, and the azo group -N=N beingdirectly attached to a ring carbon of said aryl nucleus Ar; and X is theradical of an azo coupling component.

In a preferred embodiment, the aryl nucleus Ar is a benzene nucleus, andsuch die developers may be represented by the formula:

Zn In wherein Y, Z, n, X and m have the same meaning as above.

As illustrations of suitable coupling components or couplers from whichX may be derived, mention may be made of phenols and aromatic amineshaving a free position ortho or para to the hydroxyl or amino group,e.g., phenol, anilines, naphthols, anthrols, naphthylamines, etc.;heterocyclic aromatic compounds containing hydroxyl or amino groups,such as pyrazolones or pyrroles; aliphatic or clicyclic activatedmethylene couplers, i.e., compounds having a aliphatic or alicyclicmethylene group activated by two adjacent keto, aldehyde, ester ornitrile groups, which may be the same or different, or a keto, aldehyde,ester or nitrile group in combination with an amide group, e.g.,1,3-diketones or fl-ketonic acid arylamides; etc., and substitutedderivatives thereof. Examples of groups which may be present in suchsubstituted derivatives include alkyl, sulfo, alkoxy, aryl, aryloxy,amino, keto, alkylamino, arylamino, hydroxyl, cyano, alkylamido,arylamido, carbalkoxy, carboxamido, sulfonamido, etc.

As used herein with reference to X, the expression radical of a phenoliccoupler is intended to refer to hydroxyphenyl, hydroxynaphthyl,hydroxyanthryl, etc. radicals, and substituted derivatives thereof; theexpression radical of an aromatic amino coupler is intended to refer toaminophenyl, aminonaphthyl, etc. radicals, and substituted derivativesthereof; and the expressions radical of a heterocyclic aromatic coupler,radical of an aliphatic activated methylene coupler and radical of analicyclic activated methylene coupler are to be similarly construed.

pared by diazotizing a compound of the formula:

wherein Ar, Z, n and Y have the same meaning as above, and particularlya derivative wherein the hydroxyl groups of Y are protected, e.g., anO-acylated derivative, e.g., the 0,0-diacetate, and coupling thediazotized compound into the desired coupling component providing X.Preferably Ar is a benzene nucleus. The preparation of protectedderivatives of these amino compounds, such as the bis-acetoxyderivatives, is described later in this ap plication. Where N is 1 andat least one Z is alkoxy, such Z is preferably ortho to the amine group.

As indicated above, in the aryl nucleus Ar preferably is a benzenenucleus, and the preferred group of diazotizable compounds may berepresented by the formula:

wherein Z, n and Y have the same meaning as above.

The preferred compounds within the group represented by Formula C are:

p-Aminophenyl-hydroquinone and IIIH, n:

m-Aminophenyl-hydroqulnone As examples of other compounds within FormulaC useful in preparing the dye developers of Formula A, mention may bemade of:

2- (p-aminophenyl 5-methyl-hydroquinone 2- (p-aminophenyl5-chloro-hydroquinone 2- 3 -methyl-4'-aminophenyl hydroquinone 2-(p-aminophenyl 5 ,6-dimethyl-hydroquinone 2- (4-aminonaphthylhydroquinone 2- (m-aminophenyl 5-methyl-hydroquinone 2- (4'-amino-3'-methoxy-phenyl hydroquinone 2- (p-aminophenyl 6-methyl-hydroquinon'e2- (p-aminophenyl 5-bromo-hydroquinone 2- 4'-amino-2',5-dimethoxy-phenyl) hydroquinone 2r (4'-amino-2'- chloro-phenyl)hydroquinone 2- (.4-amino-2'-methyl-phenyl hydroquinone It will beunderstood that the selection of particular alkyl and alkoxy groups inthe compounds of Formula C may be varied as desired, so long as theresulting dye developer is capable of being dissolved in the alkalinephotographic processing solution and of transferring by diffusion withina reasonable imbibition time. The selection of solubilizing groups assubstituents of the azo coupler radical, including their exclusion orinclusion, provides a useful means of modifying the solubility anddiffusion properties of the resulting dye developer to meet therequirement of any particular application.

The azo coupling is generally performed at a pH which is preferably notgreater than about 9. The hydroxy groups of Y are protected duringdiazotization and coupling, as by the formation of a bis-acetoxyderivative.

By the use of two moles of the diazonium salt to each mole of thecoupling component, one may couple twice into certain of the azocoupling components which provide the azo coupling radical X, and whichhave two available coupling positions, as, for example, phenols andaromatic amines such as 1,6-dihydroxy naphthalene and1,5-diaminonaphthalene.

Where the azo coupling component is a phenolic coupler, and particularlyan a-naphthol, it has been found that coupling ortho to the hydroxylgroup gives a dye developer of superior color properties.

As examples of suitable dye developers within the scope (XXVI) OH no N/1-phenyl-3-trifluoromethy1-4- [D- (2 ,5'-dihydroxypheny1)pheny1uzo]-5-pyrazolone (XXVII) Q :N c-NH-ouna no-n (XXVIII) (XXIX) onQN=N ii-Nn-cnn, y 110] E H,

1-phenyl-3-Nn-heptylcarbamyl-4- [p- 2' ,5'-dihydroxyphenylpheny1azo1-5-pyruzolone XX on 1-phenyl-3-N-B-hydroxyethylcarbamyl-l- [D-2',5'-dihydroxyphenyl)-phenylazo]--pyrazolone (XXXI) 1-pheny1-3-(N-2'-ethylhexylcarbamyl) -4- [p- (2' ,5'-dihydr0xyphenyl) -pheny1azo]-5'pyrazolone (XXXII) 2- [p (2',5'-dihydroxyphenyl)-phenylazo]-4-eth0xyethoxyethoxy-l-naphth (XXXIII) OH. O

2- P- 2,5'-dlhydroxyphenyl) -phenylazo]-4-methylsulfone-1- naphthol(XXXIV) 1- (o-carboxyphenyl) -3-carboxanil1do-4- [p-(2',5'-dihydroxyphenyl) -phenylazo1-5-pyrazolone As examples ofadditional coupling components which may be used to provide X, mentionmay be made of:

The novel dye developers of this invention are to be distinguished fromthe compounds disclosed and claimed in the copending applications ofElkan R. Blout, Milton Green and Howard G. Rogers, Serial No. 612,045,filed September 25, 1956 (now abandoned), and Serial Nos. 144,816 [nowUS. Patent No. 3,134,672, issued May 26, 1964], and 145,978 [now' US.Patent No. 3,134,764, issued May 26, 1964], both filed October 18, 1961,as continuationsdn-part of said Serial No. 612,045, by the fact thatthe: aryl nucleus Ar is directly attached to the phenyl ring of Y. Thedye developers of this invention unexpectedly have been found to givehigher film speed .(exposure index), and better. control or ratiobetween D and D when employed in diffusion transfer processes, ascompared with similar dye developers of the just mentioned Blout et a1.applications. The dye developers of this invention also are superiortodye developers such as phenylazo hydroquinone in that the resultingdye transfer images are more stable, particularly as to heat andhumidity.

One general-method of preparing compounds within Formula C utilizes theMeerwein arylation reaction, in which benzoquinone or an alkyl orhalogen substituted benzoquinone is reacted with the appropriatediazotized nitroaniline or hitronaphthylamine, and reducing theresulting nitroarylbenzoquinone product. The hydroquinonyl hydroxylgroups are acylated prior to diazotizing the amine group.

An alternative method of preparing compounds within Formula C is toreact the desired diazotized nitroaniline or nitronaphthyl amine with,e.g., hydroquinone, followed by reduction to the desired amino product.The hydroquinonyl hydroxyl groups may be acylated before or afterreduction of the nitro group.

The following examples of the preparation of compounds within Formula Care given for purposes of iilustration only.

Example 1 27.6 g. of p-nitroaniline was dissolved in a hot solution of60 cc. of water and 60 cc. of concentrated hydrochloric acid, andpoured, with stirring, onto 500 g. of ice and 100 cc. of water in aflask shielded from light. A solution of 14 g. of sodium nitrite in 56cc. of water was added rapidly below the surface of the suspension. 10 Nsodium hydroxide solution was added until the solution was still acidbut no longer turned Congo Red paper blue. The reaction mixture wasfiltered into a' funnel shielded from light, and added dropwise, at 10C.,to 24.2 g. of hydroquinone dissolved in 120 cc. of water. Theresulting solution was stirred for an hour and then filtered. Theprecipitate was dissolved in 300 cc. of alcohol and precipitated into asalt and ice mixture to yield 29 g. of 2-(p nitrophenyl)-hydroquinone asa light yellow precipitate, M.P. 214220 C. Recrystallization from xyleneraised the melting point to 219-2215 C.

27.4 g. of Z-(p-nitrophenyl)-hydroquinone in 250 cc. of acetic anhydrideand 2 cc. of sulfuric acid was heated on a steam bath 'for one halfhour,- and then poured onto excess ice. The mixture was stirred andslowly warmed on a steam bath until the excess anhydride was alldecomposed. Water was added to completely precipitate the oil. Themixture was cooled in ice to crystallize the oil. After filtering, theprecipitate was recrystallized from ethanol two times to give 13.4 g. ofthe diacetate, M.P. ll41l6 C.

A solution of 1 3 g. of 2-(p-nitrophenyl)-hydroquinone- 0,0'-diacetatein 130 cc. of ethyl acetate containing 6 g. of Raney nickel catalyst washydrogenated at 32 p.s.i. overnight. The solvent was evaporated and theresidue taken up in benzene and then precipitated with HCl. Theprecipitate was recrystallized from ethanol-ether to yield 9.9 g. of2-(p-aminophenyl)-hydroquinone-0,0'-diacetate as tan glistening needles.

Example 2 The procedure of Example 1 was repeated, except that thereduction step was carried out as follows: 12.0 g. of2-(p-nitrophenyl)-hydroquinone-0,0'-diacetate in 120 cc. of ethylacetate containing 2 cc. of Raney nickel catalyst was hydrogenated at 88C. for 5.5 hours, the initial 80 cc. of concentrated HCl was addedslowly to a stirred suspension of 27.6 g. of m-nitroaniline in 200 cc.

of water, and the mixture warmed on a steam bath. The resulting slurryof the hydrochloride was rapidly cooled to -5" C., and to this was addeddropwise a solution of 13.8 g. of sodium nitrite in 25 cc. of water.Stirring was continued for one hour at 05 C., filtered and added all atonce to a stirred suspension of 25.9 g. of purified benzoquinone in anaqueous solution of sodium acetate 100 g. sodium acetate in 1200 cc.water/ice mixture containing a small amount of antifoam agent) at atemperature below 15 C. The reaction mixture was stirred for 6 hours orovernight at room temperature, and the solid filtered, washed withwater, and dried to yield 2-(mnitrophenyl)-benzoquinone as a light brownpowder, M.P. lO6-109 C.

45 g. of 2-(m-nitrophenyl)-benzoquinone was placed in a hydrogenationflask with 500 cc. of ethanol and 1.4 g. of palladium on charcoalcatalyst. Hydrogenation was efiected at room temperature, thetheoretical amount of hydrogen being consumed within 4 hours. Thehydrogenation product was isolated by filtration through Celite andevaporation of the solvent under vacuum.

The resulting 2-(m-aminophenyl)-hydroquinone (0.2 mole) was placed in aflask with 750 cc. of glacial acetic acid that had been presaturatedwith HCl gas. The resulting solution was stirred for minutes with HClgas continuously bubbled into the flask. Acetyl chloride (117 g.)

was added dropwise with stirring. A warm water bath (-50 C.) was placedunder the reaction flask for 1 hour. The light brown solid whichseparated was filtered, washed, and dried in vacuum to yield2-(m-aminophcnyl)- hydroquinone-0,0-diacetate hydrochloride.

The following examples of the preparation of dye developers within thescope of this invention are given for purposes of illustration only.

Example 4 p-Aminophenyl hydroquinone-0,0'-diacetate hydrochloride isdiazotized by adding 3.2 g. (0.01 mole) thereof to 20 cc. of water and1.6 cc. of concentrated hydrochloric acid, and treating at 5 C. with 0.7g. of sodium nitrite dissolved in 10 cc. of water.

The diazo product is added, dropwise with stirring, to a solution of 1.6g. (0.01 mole) of 1-phenyl-3-methyl-5- pyrazolone in cc. of water, 4.2g. of sodium bicarbonate and 10 cc. of ethanol, the solution havingpreviously been cooled to 5 C. The resulting yellow precipitate isfiltered and then treated, under nitrogen, with 25 cc. of ethanol and 25cc. of a 20% sodium hydroxide solution for 5 minutes at -100 C.Acidification of the resulting solution with dilute hydrochloric acidyields the desiredl-phenyl-3-methyl-4-[p-(2,5-dihydroxyphenyl)-phenylazo]-5-pyrazolone[Formula I]. Recrystallization from ethanol gives 1.15 g. (32.2% yield)of the above product as a red solid, M.P. l199 C.- The product issoluble in organic solvents such as acetone and ethanol, giving a yellowsolution. The absorption spectrum of the dye developer exhibits a A at420 ma, 6 22,400, in ethanol. Analysis of the product shows:

Calculated: C, 68.4; H, 4.7; N, 14.5. Found: C, 68.7; H, 4.9; N, 14.9.

Example 5 p-Aminophenyl hydroquinone 0,0'-diacetate hydrochloride (1.6g.; 0.005 mole) is diazotized in a manner similar to that described inExample 1.

4-benzamido-l-naphthol (1.3 g.; 0.005 mole) is added to 25 cc. ofacetone and 2.1 g. of sodium bicarbonate in 10 cc. of water and thesuspension cooled to 5 C. The diazo solution is added dropwise and thesuspension is stirred for 5 minutes. A brown-red precipitate is filteredout and dissolved in ethanol. The solution is then filtered and theproduct precipitated with water. The precipitate is filtered and the wetfilter cake hydrolyzed by heating, under nitrogen, with 20 cc. ofethanol and 20 cc. of 10% sodium hydroxide for 4 minutes. Precipitationwith dilute hydrochloric acid gives 2 [p (2,5' dihydroxyphenyl)- 13phenylazo] 4 benzamido-l-naphthol' [Formula II], the absorption spectrumof which exhibits a Amax, at 505 III/L in ethanol.

Example 6 p-Aminoph'enyl hydroquinone 0,0'-diacetate hydrochloride (19.2g.; 0.06 mole) is diazotized in a manner similar to that set forth inExample 1, and is poured into a solution of 9.2 g. of2,5-dimethoxyaniline in 200 cc. of acetone and 100 cc. of water. Sodiumacetate is added to bring the pH to about 6 and the mixture is stirredfor half an hour. After filtering, the semi-solid precipitate isdissolved in acetone and precipitated by pouring onto 1% hydrochloricacid and ice. The oily precipitate is filtered, dissolved in methylCellosolve and precipitated into an ice solution saturated with sodiumacetate and sodium chloride to give 22.5 g. of ,a yellow-orange product.Hy-

drolysis of this .product gives 4- [p- (2',5-dihydroxyphenyl)-phenylazo]-2,5-dimethoxyaniline [Formula IV], the absorptionspectrum of which exhibits a k at 444-448 mg in methyl Cellosolve,e=26,000.

Example 7 Calculated Found In the following examples all parts are givenby weight except where otherwise noted, and all operations involvinglight sensitive materials are carried out in the absence of actinicradiation. These examples are intended to be illustrative only of thephotographic use of the dye developers and should not be construed aslimiting the invention in any way.

Example 8 A photosensitive element is prepared by coating agelatin-coated film base with a solution comprising 3% of 1-phenyl-3[p-(2',5-dihydroxyphenyl) phenylazo1-4- methyl-S-pyrazolone (Formula I,as prepared in Example 4) in a solution of 4% cellulose acetate hydrogenphthalate in a 50:50 mixture, by volume, of tetrahydrofuran and acetone.After this coating has dried, a silver iodobromide emulsion is applied.An image-receiving element is prepared by coating a celluloseacetate-coated baryta paper with a solution comprising 4%N-methoxymethyl polyhexamethylene adipamide in 80% aqueous isopropanol.The photosensitvie element is exposed, and brought into superposedrelationship with said imagereceiving element as an aqueousliquidcomposition comprising:

is spread between said elements. After an imbibition periodof-approximately 1 minute, the image-receiving element is separated andcontains a yellow positive image.

Example 9 The process described in Example 8 is repeated, using, as thedye developer, 3% of 2-[p-(2',5'-dihydroxyphenyl)- i4phenylazo]-4-methoxy 1 naphthol [Formula 111]. The aqueous processingcomposition comprises:

Percent Sodium carboxymethyl cellulose 4.5 1-phenyl-3-pyrazolidone 0.2Sodium hydroxide 2.0 Potassium bromide 0.2

The image-receiving element, prepared as described in Example 8,contains a magenta, positive dye image when separated from thephotosensitive element after an imbibition period of approximately 1minute.

Example 10 When the procedure of Example 9 is repeated employing, as theimage-receiving element, a cellulose acetatecoated baryta paper whichhas been coated with a layer of polyvinyl alcohol (cast from a 6%aqueous polyvinyl alcohol solution), a purple, positive dye image isobtained.

Example 11 Use of 4-[p-(2',5'-dihydroxyphenyl) phenylazo] 2,5-

dimethoxyaniline [Formula IV] in the process described in Example 9results in a yellow, positive dye image on the image-receiving element.

Example 12 i A photosensitive element is prepared as described inPercent Sodium carboxymethyl cellulose 6.0 l-phenyl-S-pyrazolidone 0.2Sodium hydroxide 5.0 Potassium lbromide 0.5

After an imbibition period of approximately 1 minute, theimage-receiving element is separated and contains a black, positive dyeimage.

Example 13 A photosensitive element is prepared in a manner similar tothe above examples, except that the dye developer is dispersed in alayer of gelatin. The coating solution from which the dye developerlayer is coated is prepared by dissolving 0.5 g. of2-[m-(2,5'-dihydroxyphenyl)- phenylazo]-4-,s-hydroxy-ethoxyl-l-naphthol,1 cc. of cyclehexanone, and 0.5 cc. of N-n butylatcetaniilide anddiluting this solution at 40 C., with a solution comprising 5 g. of 10%gelatin solution, 1.67 cc. of water, and-0.67 cc. of Alkanol B.Emulsification is eifected 'by high speed agitation in a Waring Blendor.5 cc. of the resulting dye dispersion is added to 10 cc. of watercontaining small amounts of saponin and succinaldehyde, and then coatedon the gelatin-subcoated cellulose acetate film base. After this coatinghas dried, a green-sensitive silver iodobromide emulsion is applied andallowed to dry. A photosensitive element prepared in this manner wasexposed, and brought into superposed relationship with antriage-receiving element as an aqueous liquid composition comprising:

Water cc NaOH g 5.17

Hydroxyet-hyl cellulose (high viscosity [commercial-1y available fromHercules Powder Co., Wilmington 99, Delaware, under the trade name isspread between said elements. The image-receiving element comprises a2:1 mixture, by weight, of polyvinyl alcohol and poly-4-v-inylpyridineon a baryta paper support. After an imbibition period of approximately 1minute, the image-receiving element is separated and contains a magentapositive image.

As will be readily understood by one skilled in the art, the dyedeveloper not specifically described in the above specific examples maybe prepared by diazotization and coupling procedures similar to thoseillustrated by Examples 4 through 7, substituting the desired azocoupler and amino compound within the aforementioned Formula C.

The dye developers of this invention which have, as part of the azocoupler radical X, a l-o-carboxyphenyl-S- pyrazolone system, also areuseful in the preparation of the pyrazolone lactones disclosed andclaimed in the copending application of Samuel Dershowitz and Robert B.Woodward, Serial No. 101,264, filed April 6, 1961.

The use: of 7-amino-l-naphthol as the azo coupler radical X has beenfound to give magenta dye developers having unexpectedly superior lightstability and color characteristics. Dye developers of this type aredisclosed and claimed in the copending application of Milton Green,Terry Milligan and Daniel L. Ross, Serial No. 174,248, filed February19, 1962.

The use of 3-cyano-5-pyrazolones as the azo coupler radical X has beenfound to give yellow dye developers of unexpectedly superior lightstability and color characteristics. Dye developers containing such3-cyano-5-pyrazolone radicals are disclosed and claimed in the copendingapplication of Daniel L. Ross, Serial No. 248,240, filed December 31,1962.

The quinones of the novel azo dye developers of this invention, e.g.,

(H) OH i) $CH:

2- p-2',5'-dloxophenyl) -plicnylaz0]-4-metlioxy-1-naphtli0l may beprepared by oxidizing under conditions which do not attach the azo bond,e.g., by oxidizing with benzoquinone, chloranil, or mercuric acetate.These azo quinones are useful in the photographic processes disclosedand claimed in the copending application of Howard G. Rogers, Serial No.825,359, filed July 6, 1959, as a continuation-in-part of, andreplacement for, Serial No. 599,122, filed July 20, 1956, now abandoned.One method of preparing such a quinone is to dissolve the azo dyedeveloper and a molar excess of mercuric acetate in, e.g.,dimethylformamide, and heat the mixture, While open to the air, on asteam bath for 3 to 4 hours. Upon cooling, the insoluble mercurousacetate is filtered out and the product is precipitated by adding water.Such oxidation procedures are described in the copending application ofRichard S. Corley, Serial No. 700,276, filed December 3, 1957 [now U.S.Patent No. 3,116,279].

It should be noted that dye developers in which a hydroquinonyl groupbecomes a part of the conjugated system are sensitive to pH'changes inthe absence of sulfo or carboxyl groups in the dye developer molecule.Thus 1 phenyl-3-[p-(2',5'-dihydroxyphenyl)-phenylazo] 4-methyl-S-pyrazolone is yellow under neutral or acid conditions.Application of approximately 1.5% aqueous sodium hydroxide solution to ayellow image obtained using said dye developer results in agrayish-brownish color. Since the dye developer is rendered effective bysolution in an aqueous alkaline liquid processing composition, itaccordingly is necesary to assure that the environment in which thetransferred and unreacted dye developer is deposited has or is capableof attaining the requisite pH value affording the desired color to thediffused dye developer. This may be accomplished by use of a volatilebasic compound such as diethylamine in the liquid processingcomposition. If sodium hydroxide is utilized in the processing liquid,it becomes carbonated after processing and by contact with the air andthis is effective to provide the desired pH change. Further control ofthe pH of the transferred and unreacted dye developer may be had byutilizing an image-receiving element which is difiicultly penetrable byalkali, for example an appropriate nylon such as N-methoxymethylpolyhexamethylene adipamide, or by the use of a receiving element inwhich an acid or an acid-forming compound, e.g., oleic acid, has beenincorporated.

The dye developers of this invention are also useful in integralmultilayer photosensitive elements for use in multicolor diffusiontransfer processes. As an example of such photosensitive elements,mention may be made of the photosensitive elements disclosed and claimedin the copending U.S. application of Edwin H. Land and Howard G. Rogers,Serial No. 565,135, filed February 13, 1956, wherein at least twoselectively sensitized photosensitive strata are superposed on a singlesupport and are processed, simultaneously and without separation, with asingle common image-receiving element. A suitable arrangement of thistype comprises a support carrying a red-sensitive silver halide emulsionstratum, a green-sensitive silver halide emulsion stratum and ablue-sensitive silver halide emulsion stratum, said emulsions havingassociated therewith, respectively, a cyan dye developer, a magenta dyedeveloper and a yellow dye developer. In one of the preferredembodiments of photosensitive elements of this type, the dye developersare disposed in separate alkali-permeable layers behind thephotosensitive silver halide emulsion stratum with which they areassociated.

The photosensitive elements within the scope of this invention may beused in roll film units which contain a plurality of photosensitiveframes. The photosensitive elements of this invention are especiallyuseful in composite roll film intended for use in a Polaroid LandCamera, sold by Polaroid Corporation, Cambridge 39, Massachusetts, or asimilar camera structure such, for example, as the camera forming thesubject matter of U.S. Patent No. 2,435,717, issued to Edwin H. Land onFebruary 10, 1948. In general, such composite roll films comprise aphotosensetive roll, a roll of image-receiving material and a pluralityof pods containing an aqueous alkaline processing solution. The rollsand pods are so as sociated with each other that, upon processing, thephotosensitive element may be superposed on the image-receiving elementand the pods may be ruptured to spread the aqueous alkaline processingsolution between the superposed elements. The nature and construction ofthe pods used in such units are well known to the art. See, for example,U.S. Patents Nos. 2,543,181 and 2,634,886, issued to Edwin H. Land.

It will be noted that the liquid processing composition may contain oneor more auxiliary or accelerating silver halide developing agents, suchas p-methylaminophenol (Metol); 2,4 diaminophenol (Amidol);benzylaminophenol; hydroquinone; a substituted hydroquinone such astoluhydroquinone, phcnylhydroquinone, or 4-methylphenylhydroquinone; ora 3-pyrazolidone such as lphenyl-3-pyrazolidone. These silver halidedeveloping agents are substantially colorless, at least in theirunoxidized form. It is possible that some of the dye developer oxidizedin exposed areas may be oxidized by an energy transfer reaction withoxidized auxiliary developing agent.

In addition, development may be effected in the presence of an oniumcompound, particularly a quaternary ammonium compound, in accordancewith the processes disclosed and claimed in the copending application of1'] Milton Green and Howard G. Rogers, Serial-No. 50,851, filed August22, 1960.

The dye developers of this invention may be used also in conventionalphotographic processes, such as tray or tank development of conventionalphotosensitive films, plates or papers to obtain black and white,monochromatic or toned prints or negatives. By way of example, adeveloper composition suitable for such use may comprise an aqueoussolution of approximately 1-2% of the dye developer, 1% sodiumhydroxide, 2% sodium sulfite and 0.05% potassium bromide. Afterdevelopment is completed, any unreacted dye developer is Washed out ofthe photosensitive element, preferably with an alkaline washing mediumor other medium in which the unreacted dye developer is soluble. Theexpression toned is used to designate photographic images wherein thesilver is retained with the precipitated dye, whereas monochromatic isintended to designate dye images free of silver.

It should be noted that the dye developers of this medium areself-sufiicient' to provide the desired color image and do not dependupon coupling reactions to produce the desired color. They thus providea complete departure from conventional photographic color processes inwhich the color is produced by a coupling reaction between a colorformer or coupler and the oxidized developing agent, as well asso-called auto-coupling processes in which color is obtained by areaction of the oxidized developing agent with unoxidized developingagent.

It will be apparent that, by appropriate selection of theimage-receiving element from among suitable known opaque and transparentmaterials, it is possible to-obtain either a c'olore'd positivereflection print or a colored positive transparency. Likewise, theinventive concepts herein set forth are adaptable for multicolor work bythe use of special photographic materials, for example, film materialsof the type containing two ormore photosensitized elements associatedwith an appropriate number of image-receiving elements and adapted to betreated with one or more liquid processing compositions, appropriate dyedevelopers suitable to impart the desired subtractive colors beingincorporated in the photosensitized elements or in the liquid processingcompositions. Ex-

amples of such photographic materials are disclosed in US. Patent No.2,647,049 to Edwin H. Land.

As examples of useful image-receiving materials, mention may be made ofnylon, e.g., N-methoxymethyl-polyhexarnethylene adipamide, polyvinylalcohol, and gelatin, particularly polyvinyl alcohol or gelatincontaining a dye mordant such as poly-4-vinylpyridine. Theimage-receiving element also may contain a development restrainer, e.g.,1-phenyl-5-mercaptotetrazole, as disclosed in the copending applicationof Howard G. Rogers and Harriet W. Lutes, Serial No. 50,849, filedAugust 22, 1960.

The dye developers herein set forth are also useful in the formation ofcolored images in accordance with the photographic products andprocesses described and 18 be interpreted as illustrative and not in alimiting sense.

What is claimed is:

l. A photographic developer composition comprising an aqueous solvent,an alkaline material soluble therein, a silver halide developing agentwhich is substantially colorless in at least its unoxidized form, and anazo dye developer of the formula:

wherein Y is selected from the group consisting of pdihydroxyphenyl,o-dihydroxyphenyl radicals and alkyl and halogen nuclear substitutedp-dihydroxyphenyl and o-dihydroxyphenyl radicals; Ar is a divalent arylnucleus directly attached to said phenyl ring of Y and selected from thegroup consisting of benzene and naphthalene nuclei, said -N=N groupbeing directly attached to a ring carbon of said aryl nucleus; each Z isselected from the group consisting of halogen, alkoxy and alkylradicals; n is from 0 to 2, inclusive; m is from 1 to 2, inclusive; andX is the radical of an azo dye coupler linked to said -N=N group andcompleting said azo dye developer, said Y providing the only silverhalide developing radicals in said azo dye developer.

2. A photographic developer composition as defined in claim 1, whereinAr is phenyl, n is 0, m is 1, and Y is 2,5-dihydroxyphenyl.

3. A photographic developer composition as defined in claim 1, wherein Xis a phenolic azo coupler radical.

4. A photographic developer composition as defined in claim 1, wherein Xis an aromatic amino azo coupler radical.

5. A photographic developer composition as defined in claim 1, wherein Xis a heterocyclic aromatic azo coupler radical.

6. A photographic developer composition as defined in claim 1, wherein Xis selected from the group consisting of aliphatic and alicyclicactivated methylene azo cou pler radicals.

claimed in US. Patent No. 2,968,554, issued to Edwin H. Land on. January17,, 1961.

The novel compounds herein disclosed are also for use as dy'es fortextile fibres, such as nylon. I

In the preceding portions of the specification the expression color hasbeen frequently used. This expressuitable sion is intended to includethe use of a plurality of colors 7. A photographic developer compositionas defined in claim 1, wherein said silver halide developing agent is a3-pyrazolidone.

8. A photographic developer composition as defined in claim 1, whereinsaid silver halide developing agent is a hydroquinone.

9. Aphotographic developer composition comprising an aqueous alkalinesolution of 1-phenyl-3-methyl-4-[p-(2,5-dihydroxyphenyl)-phenylazo]-5-pyrazolone and a silver halidedeveloping agent which is substantially colorless in at least itsunoxidizedform.

10. A photographic developer composition comprising an aqueous alkalinesolution of2-[p-(2',5-dihydroxyphenyl)-phenylazo]-4-benzamido-l-naphthol and asilver halide developing agent which is substantially colorless in atleast its unoxidized form.

11. A photographic developer composition comprising an aqueous alkalinesolution of 2-[p-(2',5-dihydroxyphenyl)-phenylazo]-4-methoxy-1-naphtholand a silver halide developing agent which is substantially colorless inat least its unoxidized form.

12. A photographic developer composition comprising an aqueous alkalinesolution of 4-[p-(2',5'-dihydroxyphenyl)-phenylazo]-2,5-dimethoxyaniline and a silver halidedeveloping agent which is substantially colorless in at least itsunoxidized form.

13. A photographic developer composition comprising an aqueous alkalinesolution of2,6-bis-[p-(2',5'-dihydroxyphenyl)-phenylazo]-1,5-naphthalene diamineand a silverhalide developing agent which is substantially colorless inat least its unoxidized form.

14. A photographic product comprising a support, a silver halideemulsion in a layer carried by said support and an azo dye developer ina layer carried by said supwherein Y is selected from the groupconsisting of pdihydroxyphenyl, o-dihydroxyphenyl radicals and alkyl andhalogen nuclear substitued p-dihydroxyphenyl and o-dihydroxyphenylradicals; Ar is a divalent aryl nucleus directly attached to said phenylring of Y and selected from the group consisting of benzene andnaphthalene nuclei, said --N=N-- group being directly attached to a ringcarbon of said aryl nucleus; each Z is selected from the groupconsisting of halogen, alkoxy and alkyl radicals; n is from to 2,inclusive; m is from 1 to 2, inclusive; and X is the radical of an azodye coupler linked to said -N=N group and completing said azo dyedeveloper, said Y providing the only silver halide developing radicalsin said azo dye developer.

15. A photographic product as defined in claim 14, wherein said azo dyedeveloper is 1-phenyl-3-methyl-4-[p-(2',5'-dihydroxyphenyl)-phenylazo]-5-pyrazo1one.

16. A photographic product as defined in claim 14, wherein said azo dyedeveloper is2-[p-(2',5-dihydroxyphenyl)-phenylazo]4-benzamido-1-naphthol.

17. A photographic product as defined in claim 14, wherein said azo dyedeveloper is 2-[p-(2,5-dihydroxyphenyl)-phenylazo]-4-methoxy-l-naphthol.

18. A photographic product as defined in claim 14, wherein said azo dyedeveloper is 4-[p-(2,5'-dihydroxyphenyl)phenylazo]-2,5-dimethoxyaniline.

19. A photographic product as defined in claim 14,

wherein said azo dye developer is 2,6-bis-[p-(2,5'-dihywherein Y isselected from the group consisting of pdihydroxyphenyl,o-dihydroxyphenyl radicals and alkyl and halogen nuclear substitutedpdihydroxyphenyl and o-dihydroxyphenyl radicals; Ar is a divalent arylnucleus directly attached to said phenyl ring of Y and selected from thegroup consisting of benzene and naphthalene nuclei, said -N=N groupbeing directly attached to a ring carbon of said aryl nucleus; each Z isselected from the group consisting of halogen, alkoxy and alkylradicals; n is from 0 to 2, inclusive; m is from 1 to 2, inclusive; andX is the radical of an azo dye coupler linked to said N=N, group andcompleting said azo dye developer, said Y providing the only silverhalide developing radicals in said azo dye developer to provide in saidemulsion an imagewise distribution of unoxidized dye developer inundeveloped areas of said emulsion, and transferring at least part ofsaid imagewise distribution of unoxidized dye developer by imbibitionfrom said emulsion to an image-receiving layer in superposedrelationship with said emulsion to impart a transfer image in color tosaid image-receiving layer.

22. The process as defined in claim 21, wherein Ar is phenyl, n is 0, mis 1, and Y is 2,5-dihydroxyphenyl.

23. The process as defined in claim 21, wherein said dye developer isdisposed prior to exposure in a photosensitive element containing saidemulsion and the solution containing said dye developer is formed bypermeating said photosensitive element with an aqueous alkaline liquidcapable of solubilizing said dye developer.

24. The process as defined in claim 23, wherein said 20 liquid isintroduced by being spread in a substantially uniform layer between saidphotosensitive element and an image-receiving element including saidimage-receiving layer as said elements are brought into superposedrelationship.

25. The process as defined in claim 24, wherein said liquid contains athickener for increasing viscosity and for facilitating the spreadingthereof between said photosensitive element and said image-receivingelement.

26. The process as defined in claim 21, wherein said dye developer isdissolved in an aqueous alkaline solution prior to application thereofto said exposed emulsion.

27. A process as defined in claim 21, wherein X is a phenolic azocoupler radical.

28. A process as defined in claim 21, wherein X is an aromatic amino azocoupler radical.

29. A process as defined in claim 21, wherein X is a heterocyclicaromatic azo coupler radical.

30. A process as defined in claim 21, wherein X is an azo couplerradical selected from the group consisting of aliphatic and alicyclicactivated methylene couplers.

31. A process as defined in claim 21, wherein said dye developer is 1phenyl 3 methyl 4 [p (2',5- dihydroxyphenyl)phenylazo]5-pyrazolone.

32. The process as defined in claim 21, wherein said dye developer is2-[p-(2',5'-dihydroxyphenyl)phenylazo]-4-benzamido-l-naphthol.

33. The process as defined in claim 21, wherein said dye developer is2-[p-(2,5'-dihydroxyphenyl)phenylazo]-4-methoxy-l-naphthol.

34. The process as defined in claim 21, wherein said dye developer is4-[p-(2',5'-dihydroxyphenyl)phenylazo]-2,5-dimethoxyaniline.

35. The process as defined in claim 21, wherein said dye developer is2,6 bis [p (2',5' dihydroxyphenyl)- phenylazo]-1,5-naphthalene diamine.

36. A process as defined in claim 21, whereinsaid aqueous alkalinesolution includes a silver halide developing agent which issubstantially colorless in at least its unoxidized form.

37. A process as defined in claim 36, wherein said silver halidedeveloping agent is a 3-pyrazolidone.

38. A process as defined in claim 36, wherein said silver halidedeveloping agent is a hydroquinone.

39. The process which comprises developing an exposed photosensitivesilver halide emulsion with an aqueous alkaline solution of an azo dyedeveloper of the forwherein Y is selected from the group consisting ofpdihydroxyphenyl, o-dihydroxyphenyl radicals and alkyl and halogennuclear substituted p-dihydroxyphenyl and o-dihydroxyphenyl radicals; Aris a divalent aryl nucleus directly attached to said phenyl ring of Yand selected from the group consisting of benzene and naphthalenenuclei, said -N=N- group being directly attached to a ring carbon ofsaid aryl nucleus; each Z is selected from the group consisting ofhalogen, alkoxy and alkyl radicals; n is from 0 m2, inclusive; m is from1 to 2, inclusive; and X is the radical of an azo dye coupler linked tosaid N=N group and completing said azo dye developer, said Y providingthe only silver halide developing radicals in said azo dye developer.

References Cited by the Examiner UNITED STATES PATENTS (Other referenceson following page) 21 22 UNITED STATES PATENTS 2,698,244 12/54 Land.3,134,672 5/64 310m et a1. 9629 2,819,662 1/ 58 Land- 3,135,604 6/64Green et a1. 9629 OTHER REFERENCES OTHER REFERENCES 5 Venkataraman: TheChemistry of Synthetic Dyes, vol. Mees: The Theory of the PhotographicProcess, Mac- 1, Academic Press, Inc., New York, 1952, pp. 358 andmillan, NY. (1954), page 556. 359. R f s d b th A H t Henn et 21].:Properties of Developing Agents, Photoe creme le y e Pp can graphicScience and Technique, PSA Technical Quar- UNITED STATES PATENTS 1oterly, November 1954, pp. 126-130. 2,148,252 2/39 Zwilgmeyer. Lubs: TheChemistry of Synthetic Dyes and Pigments, 2,374,158 4/45 Knight et a1.Reinhold, New York, 1955, p. 670.

2,423,542 8/47 Wright. 2,543,691 5 Friedmam NORMAN G. TORCHIN, PrimaryExaminer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,183,089 May 11, 1965 Myron S. Simon It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 2, line 32, for "developer" read developers column 3, line 37,for "clicyclic" read alycyclic line 38, for "having a" read having ancolumn 13, line 26, for "p-Z 5 read p- [2 5 column 14 line 30, for I"1300" read 13,000 line 31, for "in methyl Cellosolve" read in a methylCellosolve line 52, for "ethoxyl" read ethoxy column 15, line 8, for"developer" read developers line 43, for "2- [p-Z," read 2-[p-[2 column16, line 47, for "photosensetive" read photosensitive column 19, lines33 and 34, for "dihydroxy" read dihydroxyphenyl Signed and sealed this25th day of July 1967.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

21. IN A PROCESS OF FORMING A PHOTOGRAPHIC IMAGE IN COLOR, THE STEPSWHICH COMPRISE DEVELOPING AN EXPOSED SILVER HALIDE EMULSION WITH ANAQUEOUS ALKALINE SOLUTION CONTAINING AN AZO DYE DEVELOPER OF THEFORMULA: